What initiatives, policies, and strategies can advance carbon pricing?

Many experts agree that placing a price on carbon pollution is a highly economically-efficient way to tackle climate change. A carbon price creates incentives for the development and adoption of innovative low carbon technologies and practices across the economy. This could involve a carbon tax, a cap-and-trade system, hybrid systems, rebates, or other solutions, and could be revenue-natural, meaning it could reduce other kinds of taxes simultaneously, or the revenue from allowances auctions could be reinvested.

This contest asks entrants for novel policies, new mobilization strategies, measurement technologies, or combinations of approaches applied across scale (e.g., sector, city, state/province, region, national, or international levels) that could lead to the enactment of a price on carbon, or regional or international collaboration on carbon pricing. What are strategies, policy proposals, public mobilization, or other ideas that could advance carbon pricing strategies at the national or subnational level in any country?